Refrigerating apparatus and method



4 Sheets-Sheet l Il Il )I ll iled Deo D. H. KILLEFFER ET AL REFRIGERATING APPARATUS AND METHOD Oct. 25, 1932.

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ATTORN EY Oct. 25, 1932. D. H. KTLLEFFER ET AL 1,883,939

REFRIGERATING APPARATUS AND METHOD Filed Deo. 23. 1950 4 Sheets-Sheet 5 ATTORNEY Oct. 25, 1932. D. H. KILLEFFER ET AL 1,883,939

REFRIGERATING APPARATUS AND METHOD Filed Dec. 23, 1930 4 Sheets-Sheet 4 ./fjff" 127128 j? l ff.

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Maio/ Patented ocr. 2s, 1932 UNITED STATES VPn'relsxr OFFICE 1 i DAVID H. IKILLEFFEIR, YONXEBS, AND CHARLES L. J' ONES, 0F PELHAM, NEW` YORK,

ASSIGNORS TODRYICE EQUIPMENT CORPORATION, F NEW YORK, N. Y., A CORPO- BATION .OF DELAWARE BEFRGERATING A PABATUS AND METHOD Application led December 23, 1830.v Serial-No. 504,248.

Our present invention is related to that set forth in application Ser. No. 447,470, of which David H. Killeifer is the sole in ventor,.in that it concerns refrigerators of a type adapted to employ very intense refrigerants, particularly solid carbon dioxide, and to methods of and apparatusv for solving special problems connected with `the employment of solid carbon dioxide for .10 commercial refrigerating purposes. The ing ventionV is particularly adapted for and is shown as embodied in a refrigerator car, storage, rooms, household refrigerators or the like, particularly where the intensely cold g1g refrigerant and gas therefrom are utilized to maintamclosely regulated temperatures, vusually far above the evaporation point of the refrigerant-and usually near and above the freezin point of water. go Among te unique factors involved in the use of solid carbon dioxide as a refrigerant for such purposes, are the following:

Solid Vcarbon dioxide sublimes directly to a gas, without any intermediate liquid state,

86v at a temperature of approximately 110 F.

below zero, although the temperature may var within wide limits above and below sai temperature, according to the pressure, and the percentage of air in the atmosphere )0 that bathes the solid carbon dioxide.

The refrigerantI action is two-fold, that is to say,-'thel local heat absorbed by change of the carbon dioxide from solid to gaseous state is the major factor, the other factor being the resulting gas, which absorbs a substantial amount of heat while warming up vto normal temperatures.

vThecarbon dioxide gas is remarkably su= perior to' air as'a Yheatinsulator even where i air even when both are'at the same temperature. Hence, whenever the fresh cold gas is free to do so, it will flow downward, displacing upward, air, air and gas mixture and even pure carbon dioxide gas of higher temperature, and in a gas-tight structure, such as ours, it would, after sufficient'gas has been generated, supply an atmosphere within the refrigerated chamber, substantially free of air. Thesequalities may be used to any desired extentin the present invention by dischargingl all the gas into the refrigerated space; or mingling part or all of it with the air circulation; or discharging part or all of it outside of the refrigerator.`

If there are any low level openings or leaks, either in a refrigerated space or in any otherV container in-which it is held, the cold gas will drain downward by gravity through the lower openings or leaks. If said lower openings or leaks are large enough, the downowing gas will be replaced'by air or warmer gas from the exterior, and even if the lower openings or leaks are Very small, there will be a suction elfect which will draw in air, in case thereare any high level openings or leaks.Y Consequently, we prefer to use a gastight structure so as to ensure efficiency of operation, particularly when all the gas is discharged into the refrigerated space.

It has been proposed to utilize these qualities in various ways, most of which involve locating the solid `carbon dioxide at a high level in the refrigerated space where the air is warmest and whereA there is opportunity for gravity downiow of the gas generated by the heat thus absorbed. In some cases the gas is discharged directly into the atmos-` phere of the car of the refrigerated space and the heat is applied to evaporate the refrigerant by the general thermo circulation of the atmosphere in said space for the purpose and with the result that the heavy gas flowing downward gradually displaces the air upward until the atmosphere is largely carbon dioxide gas. culation of the gas is confined to'l conduits in` U-relation such that the heavy cold gas flows downward in one conduit and as it warms up, rises in another conduit and is finally discharged into the refrigerated space or, in cer- In othercases, the thermo cir-7 tain cases, outside of said space. Another case is that set forth in said application Ser. No.` 447.470. in which gas-tight conduits are l employed fo'r thermo circulation of the gas downward from the refrigerant upward in `heat exchange relation with the refrigerated vwhen used in connection with products likely to be harmed;` also in said application. the temperature is partly controlled by controlling a circuit of thermo circulation of the air from the top of the refrigerated space down-- ward iii-intimate heat exchange relation with the refrigerant; also means whereby the excess gas may be discharged into a refrigerated space is provided so that the advantages of the gas may be available where the products are not likely to be injured thereby.

. Our present invention has somewhat similar objects in view. particularly as concerns surely and certainly keepingv the gas out of the refrigerated space when this is desired, and one feature contributing to this is discarding attempt at gravity thermo circ-ulation of the gas through a conduit system. the gas in the present case being led directly from the top of a substantially gas-tight containerr or bunker into a simple large area chamber or conduit in the top of the car where the air is hottest and the refrigerant values of the gas niav be effectivelv availed-of. the gas warmed in said conduit being discharged through short lengths of metal pipe of rugged construction such that gas leak into the refrigerated space may be prevented with far greater certainty b v construction much cheaper and simpler than where elaborate thermo circulation conduits are employed.

In such a situation. the gas not being recirculated to serve as heat transfer medium. the' air in the refrigerated space "s relied upon to perform this function. the warm air being drawn `from a remote part of the refrigerated space which in the case of a refrigerator car is. near the middle of the car,

and conveyed in'conduits to the solid carbon y dioxide container in the remote -cnds of the car where saidv air is brought into intimate heat exchange relation with large area heat absorbing surfaces ofgood conducting Inavterial such as metal. preferably a, vertical l by said surfaces-Hows down the same. drawine in the warm air at the fair end of the intake. Preferably. the lower outlet of the air chilling space is throttled to suchlextent as chilled air. j It will thus be seen that in the normal premav be desired to retard the down rush of the ferred operation for which our apparatus is prmarily designed, the gas has no thermo circulation, butisA forced through heat absorbing conduits directly to the exterior of the car, while the normal thermo circulation of the air isguided and controlled from a remote region 'of the refrigerated space to the top of and downward along thev solid carbon dioxide bunker, thereby distributing the major portion of the refrigerant value by closed circuit thermo circulation, the up leg,

ofwhich comprises the entire atmosphere of the refrigerated space, while the return and down leg comprises the guided and controlled flow through the conduits; in heat transfer relation to the refrigerant. A

Air, without gas. is of particular advantage as the sole medium for such circulation, particularly where relatively high, that is,

above freezing temperatures, are to be preserved in the refrigerated space because both the up leg and down leg of the circulation are of the same specific gravity and the only tendency to stratification and low-level localizing of cold is due to the differences of temperature in the different parts of the circuit. Moreover, the specific heat of air is', relatively small and it is more quickly chilled and warmed. Consequently, relatively larger quantities of air may be circulated at higher speed and less .dangerously low temperatures than in the case of pure carbon dioxide gas, or even gas air mixtures. Even if cooled 15 to 20 degrees below freezing, air has such small specific heat and its specific gravity is so slightly decreased below that of the air of the4 refrigerated space, that it will quickly warm and diffuse therein without danger of freezing the products, thus avoiding a danger which frequently attends the use of heavy, cold carbon dioxide gas.

Because of the small heat carrying capacity of the air, the circulation has to be and naturally is of higher velocity in order to transfer the vamount of heat required to keep down refrigerating temperaturto that desired for the products to be refrigerated.

In the preferredv form, this circulation is controlled by a valve at the high level intake for the warm air and the control may be by means of a thermostat located in the conduit at the intake.

Whilethe entiresystem is primarilydevised for the purpose of certainly and surely keeping gas out of the refrigerated space, we provide means whereby part or all of the gas may be discharged into said space, an important feature being an arrangement whereby any desired amount of the gas can be discharged into the air intake conduit to thoroughly mingle and diffuse with the air before it is returned for thermo circulation in the atmosy phere'of the refrigerated-space. This is in cape to the exterior atmosphere.

marked contrast to other systems wherein carbon dioxide gas, if used, is slowly and nonturbulently released at a low level in the re'- frgerated space for the express purpose of displacing upward as much air as possible. There is further provision of means for releasing the air directly into the refrigerated space so' that the latter function may be served if and when-desired.

i Other features of the invention include the provision of a structure in which the refrigerant is practicallyisolated and heat insulated as concerns direct heatabsorption from the refrigerated chamber` combined with means permitting of free flow of atmosphere from the refrigerated space into high heat exchange relatlon with the refrigerant, and with means for utilizing the refrigerant value of the cold carbon dioxide gas by high level heat absorption before permitting lit to es- Further features are the provision of a refrigerant bunker constructed so as to maintain maximum surface contact between the refrigerant and the more or less upright heat conducting walls the outer surfaces of which are exposed to the air circulation; also to provide a unitary bunker structure that may bemoved into position or removed therefrom with a minimum of costv and labor.

Other objects are the provision of a unique temperature responsive means for automatieally controlling the temperature within the refrigerator, preferably through control of the atmospheric convection currents; also positioning this means so that it is protected from damage and hidden from sight so thatl control of the apparatus is substantially foolproof.

The above and other features of the inven- .tion including various refinements and deline 4 4 of Fig. 1;

, Fig. `5 is an end view, partly in section, of the damper which controls the inlet of warm atmosphere and the automate means for con-- trolling the same; A

Fig. 6 is a vertical section taken on the line 6 6 of Fig. 5, showing in detail the auomatic means for operating 'the damper; an Y Fig. 7 is a plan View of the lower sidev of F1g.5 showing the means for setting the preferably metallic, shell 7. The bunker apparatus to operate at different temperatures. v

charopenings 8 are of conventional structure, there being preferably twoin each end of the ear. The surrounding walls-of the chamber may be of some such`material as balsa wood, which is light and a good heat insu- 1 lator, yet comparatively strong and able l'to withstand much usage'. The gas-tight casing 7 completely surrounds the car and the joints 10 of the same should be painted with red lead and rubber, or any other material which will make Athem gas-tight, particularly to carbon dioxide gas. The best practice is to weld the points where the welds can afterwards be tested for leaks butwhere this cannot be done, closely spaced rivets could be applied and special precaution taken in the painting of the joints with the material to ensure gas-tightness. The doors 9 are made with a very accurate fit so that they will alsobe gas-tight, or as nearly so as it is possible to make them.

Y Within the car, the flooring is protected by the covering'l, of any suitable material, and on top of, this covering are slats 16, preferably several sections of them, spaced apart so that the 4cold atmosphere, or lcarbon dioxide gas when the same is used, may circulate under the load as Well as through it.

In the case of the refrigerator car here shown, each half of the length of the car is served b a refrigerating system that is a substantial duplicate of the other, the refrigerant containers being in the respective ends of the car and the auxiliary-circulation controlling elements extend towards and symmetrically disposed with respect to transverse center plane of the car, but it will be understood that for shorter refrigerators such as truck bodies, only one such system will be necessary; also\that in such case, the bunker maybe located in the forward end with the conduits extending toward service doors at the rear end.

In the present case, the bunkers are supported by a skeleton frame-work, preferably 12o made with angle-irons and which consists of the base members 17, upright members 18 and diagonal members 19, the latter extending from a point 20 near the rear end o f the members 17 to a suitable point 21 in the 125 upright members 18, so as to prevent weaken-A ing or sagging by the latter members, this extends even beyond the insulation of theare riveted or fastened together at the point 22, in any suitable manner. The gussets 23 are provided for additional support.'

The bunker is supported at its rear by two upright supports 25, preferably wood, which are intermediately attached to the sides, by

the angle-irons 26.. The support 25, at its top, is bolted to the channel cross bar Q7 which bunker, as clearly shown in Fig. 4, to points adjacent thc sides 5 and 6. The front end of the bunker rests on the cross member 28 'which is preferably of wood, and protected by the metal angle-iron Q9 which is secured to the member 2S by the bolts 30, the whole being supported by the bracket 31 which is secured. as shown at 32, to the upright member 1S. 4

The bunker itself is composed of an outer metallic casing. consisting of the front 33, ends 34. inclined bottom 35, horizontal bottom 36 and back 55, and the inner metallic sheets 37 and 38, the .latter being substantially thicker tlian'tlie former. In practice it has been found very etiicient to use 1/3 inch plate for the piece 37 and 1/4 inch for 38. These 4 metallic members are preferably welded at all of their joints and have between them some good heat insulation, such as the cork 39 of about 5 inches., in thickness. strips 40 and 41 extend the length of the refrigerant container and support the inner' bottom to prevent the same from collapsing the insulation 39 due to the weight of the refrigerant.

At the rear of the refrigerant container is the heavy metallic sheet 45, of the same thickness as 38, extending across the entire length of the container and having at its rear and preferably made integral therewith. the heat radiator fins 46,also of the same heavy ror thick metal. These fins, with the walls .i5 and 47 forma plurality of vertically disposed passages 4S, having atltheir upper ends a sort of manifold 49 and at their lower ends the restricted opening 50 formed by the plate 5l which is held in place. at suitable points thraughout its length by the bolts 52 and thumbscrews 53.

Behind the wall 4T is the necessary thickl ness of insulation 39, protected by the metal casing 55. l

Leading into the passages 4S is t-he air duct 56 which extends from the manifold 49 over the top of the bunker and between the hatchways, along the roof of the car, to any con venient point near the center thereof. At the inlet end of 56 is the automatic control means 80, which will be described later.

Oii either side of the air duct 56 are the carbon dioxide gas ducts 5T connected by the pipes 58, preferably having therein unions to Vfacilitate connection with the refrigerant chamber. The ducts 57 also extend to a point near the center of the car, their ends being in The wooden y of the other unit. At some point in the pipe 60, preferably not opposite the door opening, may be placed a suitable valve 61'to allow forv passage of gas from one unit to the other or to permit of the escape of the gas from one or both units to the atmosphere through the out let conduit 62 or to vdischarge the gas from bth units into therefrigerated chamber or to permit the gas to `escape from one unit to the atmosphere and discharge the gas from the other unit into the refrigerated chamber, as desired.

Leading from the pipe 59 is the pipe 63, having at some point in its length the `valve 6i, which preferably enters the conduit 56 .through the side thereof and, if desirable,

Vutility of this pipe will be explained hereafter.

The refrigerantcontainer has the cover 79, which, preferably, is heavy enough so that its own weight will cause a substantially airtight seal through pressure on the gasket 89, which may be ofsuitable soft material, as, for instance,'sponge rubber.

The operation of the apparatus, as described tlius far is as follows:

The bunker lhaving been charged with solidI carbon dioxide and the top 7 9 replaced thereon, the cold carbon dioxide gas first fills the refrigerant container, thus maintaining the refrigerant in the unusually good heat insulating atmosphere of its own gas, and flows through the pipe 58 to the large area heat absorbing ducts 57. The pipe 58 is preferably welded to the inside, 3T, of the refrigerant container to preclude any possibility of escape of gas other than into the ducts 57.

V,These ducts being of any desirable dimensions, say 3 inchesby l2 inches, occupy coinparatively little lading space and being positioned against the ceiling are only remotely subject to damage from the refrigerated load or when loading and unloading the same, yet they are adequate for applying most of the refrigerant value of the gas, by absorbing heat from the warmest part of the refrigerated chamber. It is well known that carbon dioxide gas is very beneficial to some products, whereas, to others it may be harmful, consequently the nature of the refrigerated products determines whether or not the gas should be discharged into the refrigeratedchamber or vented to the atmosphere. This contingency may be taken care of through the valve 61. There are preferably two such ducts in communication with t-he refrigerant container and if they are placed near the sides 4 and 5 they will have a further tendency to maintain the desired low tempera'- ture and equalize the same, by absorb-ing heat entering through the sides and roof ofthe -the valves are intentionally set for such operation.

The warm atmosphere from the .refrigerator chamber, is carried, through the duct 56, from what is normally the warmest part Y of the car, i. e., near the center and roof, back over the refrigerant container, into the manifold 49 and down through the channels 48. These channels are preferably about 5 inches square, their sides being maintained at a very .ow temperature by conduction of heat to the refrigerant which rests on and against the relatlvely thick metallic surfaces 38 and 45.

The wall 47 is not as thick as the wall 45 and the fins 46 because metal will conduct heat in proportion to its thickness and the wall n.

refrigerated chamber, there may be a tend- 47 being adjacent the end of the car would have a tendency to maintain the insulation 39, at this point, and the end wall at a much lower temperature than would be desirable, for a section so remote from the refrigerated chamber. We found it desirable to extend the fins 46 far enough to reach the wall 47, but this was for structural strength and is not necessary. They could have their edges short of contact with this wall.k

If it were not for the open space or manifold 49 between the inlet end of the duct 56 andthe top of the channels 48.I the down draft would have a tendency to concentrate in those channels that are directly under the end of the duct 56, but this manifold offers the opportunity to the entering air to spread extensively to either side. To insure that the warm air will reach the en'd channels equally as well as those in the center, we have restricted the lower or outlet end of the channels to a comparatively small How section. This may be accomplished by taperingthe lower ends of the channels or in any other desired manner, but we prefer tohave the cross sectional dimensions of this end the same as the remainder of the channel and to employ a throttle plate 51 of such width as may be required to limit downflow section. The total-volume of atmosphere that can pass through the opening 50 being less than the volume of atmosphere entering through the duct 56, naturally tends to create a slight back pressure on the system at this point, the result being that there will be no greater tendency to downllow of the atmosphere through the channels near the duct 56 than there will be through the channels near the sides of the car. The bolts or screws 52 may be fastened at any convenient point, as to the fins 46, in any conventional manner, corresponding holes being cast or drilled in the plate and the same being held against the mouth of the channels by the thumbscrews 53. This construction permits of rapid and easy removal of the plate 5l so that the channels may be inspected or cleared of frost when the same has accumulated therein to an undesirable degree. The atmosphere having been in contact with the very cold surfaces, as above described, drops through the opening 50 and out under the bulkhead, back to the refrigerated chamber. e

This set-up of thermo-circulation of the `atmosphere within the refrigerated chamber,

1. e., the warm air flowing through the'duc 56 down through the channels 48 where its temperature is greatly reduced with the consequent increasing of its specific gravity, owing out under the bulkhead into the refrigerated space Vand displacing the warmer, lighter'atmosphere upwardly; continues as long as the atmosphere is allowed to flow through the duct 56.

When the gas is allowed to escape into the ency for a heavy layer or blanket of substantially pure carbon dioxide gas to accumulate in the bottoni of the chamber and build itself up to a substantial height in theehamber, in which case the great specific gravity of the gas might cause it to afford resistance, or perhaps even to completely stop the flow of air through thechannels 48, somewhat as a pool of water might act. It is a well known fact that carbon dioxide gas is about 50% heavier than/air, when both are at the same temperature' and when the. temperature of the gas is lowered this difference in weight is proportionately increased and it might happen that the weight of the atmosphere from within the refrigerated space, even though it be cooled to a very lowtemperature, will not be sufficiently heavy to force any appreciable downflow through the pool of carbon dioxide gas. For efficient operat'on, there should be complete co-mingling of the low temperature atmosphere from the channels 4'8 and the atmosphere within the refrigerated chamber and to insure such co-mingling, when the carbon dioxide gas is to be discharged into a refrigerator containing air or only small percentages of gas, we provide the pipe 63, communicating with 59 and having its other end discharging intoihe conduit 56, in the direction of the flow of atmosphere therethrough. Thiswill ensure thorough pre-mixing and will prevent the formation of too heavy a layer of carbon dioxide gas or gas air mixture in the bottom of the chamber :and will facilitate quick, uniform co-mingling of the carbon dioxide gas with the air throughoutthe atmosphere in the refrigerator. The proportion of the total of the gas discharged into the conduit 56 can be regulated through means of the valve 64. The pipe 63 should not enter the conduit in close enough proximity to the thermostat 80 to have any effect on .the operation of the latter.

The bottom 38, of the refrigerant container preferably slopes at a comparatively sharp angle Hin order that the refrigerant will always and automatically be held in contact.

,o irons 73 and 74 which are fastened in any suitable manner to the uprights 18. The bulkhead is hinged at some convenient point 75, thus forming an upper and lower section,

the lower section preferably being liftable so that access may be had to the region under the bunker, and it extends downwardly to'a point short of the floor, thereby forming the opening 76 which permits the circulation above described.

The opening 77 is merely a drain pipe to allow for the drainage of water caused by melting frost or condensation from the refrigerating apparatus, or water used in the cleaning of the interior of the car. This opening is normally kept closed by an elongated plug 78, which effectively maintains 'the air-tightness of the refrigerator, when in use.

The automatic means 80 for operating the damper 81, already referred to, is located at the inlet end of the duct 56 and positioned v within the duct. If the duct is not of suficient depth to accommodate the automatic 1neans,yits depth may be increased as shown at 82, to any required extent. The automatic means may be of any desired or conventional type, but 1n practice we have found the thermost'atic arrangement, sho'wn clearly in Fig. 6, to be very accurate and dependable.

Referring to Fig. 6, the damper 81 is shown in closed position, being flush with the abutment 81a which is secured to the down turned portions 83 of the duct 56 by the rivets 84. The damper has all four of its sides bent as shown at 85 for the purpose of strengthening it, the upper bent side, y86, hooks over the pivot rod 87 and at any convenient points in the length of the side 86, ears 88 are cut from it and arranged tosubmay pivot smoothly and easily on the rod 87, f

whlch is held in place by the lugs 90 The damper 81 is normally held in closed lposition by the springs 93, there preferably..

eing one spring at each end of the damper, fastened to the damper through means of the eye-bolts 94 and nuts 95, the same or any other convenient means being utilized to fasten the other end of the spring to the sides of the duct 56.

The thermostat consists of the outer casing 96 and the inner metallic bellows 97 which is soldered or fastened to the casing 96 in lany suitable manner. The spring 99, within the bellows, maintains it in extended position through pressure on the end piece 100, said end piece having the inward extension 101 which is made hollow except for the stop 102 and has the loosely fitting guide rod 103 positioned in the portion 104 for the purpose of preventing the bellows 97 from wobbling. T he guide rod 103 is fastened to the casing by screw cap 105 or other means holding the flange firmly against the end of casing 96. rl`his guide rod is hollow to permit of the space between the casing 96 and bellows 97 being filled with the preferred liquid, the opening in the rod 103 is then closed by the screw plug 10371.

The forward end 111, of the extension 101 is threaded as shown at 112 for the purpose of receiving the push rod 113. The guide, 114, through which the rod 113 slides may be placed at any convenient point to maintain the thrust of the rod in a straight line. Screwed to the end of the rod, nearest the damper, is the fork or yoke 115 which is locked in position by the nut 116 and between the prongs of the fork is held a roller 117 which revolves on the pin 118.

The casing 96 is attached to the base-plate 98 by brazing or otherwise, and the latter is internally threaded to receive the screw-plug 106, which is for adjusting thrust of the spring 99. f

As the temperature of the liquid in the space between the bellows 97 and the outer casing 96 increases, there will be a corresponding increase of its vapor pressure, and this increase in pressure acting on the head piece 100 and the corrugations of the bellows force the head forward, against the thrust of the spring 99, thereby forcing the roller 117 against the damper 81, through the push rod 113, thereby opening the damper. The damper is held open a Idistance varying with the vapor pressure until a lower temperature permits of a decrease ir vapor pressure within the casing 96, which will allow of therecession of push rod 113, acting under the tension of thel spring 99.

j This structure, as so far described, would permit of operation within a very limited temperature range so we have provided an adjustable means, whereby through the forward or backward movement ofthe thermostatic structure, in its entirety, automatic opi eraton'may be-had over an extremelywide temperature ran e. v

Referring to ig. 6 and Fig. 5, the baseplate 98 is attached by means of screws 124, to the plate 125, said plate being arranged for forward and backward movement. On either side of the plate and extending suiiiciently beyond its ends to maintain it steady, in its forward or backward movement, are the guide strips 126 which overlap the plate 125 as shown at 127, these guide strips being held by screws or rivets 128 to the reinforcing plate 129, said screws or rivets extending through both plates and the bottom of the duct 56 thereby holding the three elements together. The rear end of the plate 125 is bent upwardly as shown at 130 and out out to form a cradle in which the rear end of the casing 96 may rest, thus preventby the screws 137, which pass through theP lower side of the duct and the plate 129 and guides 126.

The above construction provides means whereby the thermostat may be moved either toward or away from the damper 81. If, f'or instance, the thermostat is set to operate at F. and it is desired to change it to operate, say at 32 F., this can be accomplished by turning the handle 134, to the point marked 32, the turning of the handle movy`ing the eccentric 132 in a direction to cause rearward movement of a thermostat, the result being, of course, that the push rod 113 will have to travel a greater distance than it would when set to operate at 15 and thiswould be accomplished by an increase in pressure within the casing 96 due to the higher temperature to which the casing would be exposed. This higher temperature would be' supplied by the atmosphere within the refrigerated space, because the said atmosphere would be increasing in temperature due to the lack of circulation through the system, which circulation would be prevented `as the damper 81 has been partially or wholly j closed for a longer period of timethan it would have been when set to operate at 15. This cycle would be reversed if a lower temperature were desired, the thermostat being moved closer to the damper and the push i rod 113 having a shorter distance to travel. I

Thus the thermostat, operating automatically at any desired temperature, will open heavier, so Vthat it iows downward more rapidly, thereby producing the suction that draws the warm atmosphere into the duct 56 proportionally to the difference in weight between the interior and exterior columns of atmosphere. The rapidly falling cold atmosphere, from the opening would iiow downward into the refrigerated space through the opening 76, with comparatively great force, thus reaching substantially all parts of the refrigerated chamber.

It should be understood that we do not limit ourselves to the specific structure, or arrangement as here disclosed. For instance, it is often expedient to construct the bunker so that its breadth is comparatively small and its depth comparatively great, this construction makes the channels 48 much longer, consequently keeping the flowing atmosphere in contact, with its extremely cold surfaces, for a. longer distance' than would be the case when the channels are shorter. It also per-- mits of moving the bulkhead closer to the end of the refrigerated chamber, thereby allowing more lading or paying space within the refrigerator.

Another very useful and practical addition or modification that may be made is the provision of a temporary or permanent partition 170, extending across the chamber, thereby making two separate sections, one section to be maintained at one temperature. and the other at a'difl'erent temperature; or one to have gas in its atmosphere while the other has all gas discharged outside. A light wooden frame supporting cardboard or heavy paper could be put in place at a very reasonable cost and very quickly, the same being so cheap could be thrown away at the end of a journey. Such apartition and the joints could be painted with a'material which is highly impermeable to carbon dioxide as,

.thus when it is desired to maintain a 'car on dioxide gas atmosphere in one portion of the refrigerator and maintain the other portion v substantially free of carbon dioxide gas, this result can be accom lished by the simple expedient'explained a ove.`

If the two units are to operate at the same temperature, one thermostat will suiice, but

if it is desired to operate them at different I. temperatures, a thermostat for each unit should be provided.

Our invention is particularly adaptable for large refrigerators, but it is applicable to ordinary household refrigerators, when the atmosphere of the refrigeratedspace, said means including al downflow portion serially connecting high'and low levels of said atmosphere and having an intermediate portion only, of said means, extending in close heat exchange relation with a highly conducting surface kept cold by said refrigerant, the heat exchange portion of the downflow portion being of great width and of greater flow section than the outlet thereof.

2. A refrigerator and a refrigerating system, including a substantially gas-tight receptacle for solid carbon dioxide, very highly insulated against direct heat conduction from the refrigerated space, and anon-return conduit through which the gas evaporated from the solid may bc discharged outside of said space whereby heat transfer from and evaporation of the solid by direct jheat transfer from said space is below normal requirements and gas may be kept out of the atmosphere of the refrigerated space,'in combination with means for variably transferring heat from ythe refrigerated space to the receptacle, said means including a downiow portion serially connecting high and low levels of the at- 1 mosphere of the refrigerated space and extending in close heat exchange relation with said refrigerant'receptacle.

' 3. A refrigerator and` a refrigerating Asystem, including a substantially gas-tight receptacle for solid carbon dioxide, very highly insulated against direct heat conduction from the refrigerated space, and anon-return conduit through which the gas evaporated from the solid may be discharged outside of said space whereby heat transfer from and evaporation of the solid by direct heat transfer fromy said space is below normal requireortion serially connectin ments and gas may be kept out of the atmosphere of the refrigerated space, in combina.- tion with means for variably transferring heat from the refrigerated space to the re'- ceptacle, said means including a downflow high and low l evelsjof the atmosphere o the refrigerated space and extending in close heat exchaxi e relation with said refrigerant receptacle, t e intake of said downfiow portion being from a region of the refrigerated space remote from said receptacle.

4. Arefrigerator and a refrigeratng sys- Ineans for retarding the velocity of the downbination with means for variably transferring heat from the refrigerated space to the receptacle, said means including a downilow portion serially connecting high and low levels of the atmosphere of the refrigerated Vspace and extending in close heat exchange relation with'said refrigerant receptacle and thermostatic means controlling the intake of said portion.

5. A refrigerator and a refrigerating system, including a substantially gas-tight receptacle for solid carbon dioxide, very highly insulated against direct heat conduction from the refrigerated space, and a non-return conduit through which the gas evaporated from the solid may be dischar ed outside of said space whereby heat transfer from and evaporation of the solid by direct heat transfer from said space is below normal requirements and gas may be kept out of the atmosphere of the refrigerated space, in combination with means for variabl'ytransferring heat from the refrigerated space t'o the receptacle, said means including a downflow portion serially connecting high and low levels of the atmosphere of the refrigerated space and extending in close heat exchange relation `with said refrigerant receptacle, and

flow to maintain a body of the air in heat exchange relation with the wall ofthe receptacle for a relatively long time.

6. A refrigerator anda refrigeratingl system, including a substantially gas-tight receptacle for solid carbon dioxide, very highly insulated against direct heat conduction from the refrigerated space, and a non-return conduit4 through which the gas evapo- 1 rated from the' solid maybe discharged outside'of said space whereby heat transfer from and evaporation of the solid by direct heat transfer from saidnspace is below normal relli quirements and gas may be kept out of the 121 atmosphere of the refrigerated space, in comlbination with means forvariably transferring heat from the refrigerated space to the receptacle, said means including a downow portion serially connecting high andxlow 12 levels of the atmosphere of the vrefrigerated space and extending in close heat exchange relation with said refrigerantreceptacle, the

heat exchange portion of the d ownlow portion being of great Width as 'compared with 13 the inlet and of great flow section as compared with the outlet.

7. A refrigerator and a refrigerating system, including a substantially gastight receptacle for solid carbon dioxide, very highly insulated against direct heat conduction from the refrigerated space, and a non-return conduit through which the gas evaporated from the solid is conducted outward in heat exchange relation with a high level portion of the refrigerated space and thence through an outlet outside of said space whereby heat transfer and evaporation of the solid by direct heat transfer from said space is below normal requirements, and gas may be kept out of the atmosphere of the refrigerated space, in combination with means for variably transferring heat from the air of the refrigerated space to said receptacle, including a downflow portion serially connecting high and low levels of the refrigerated space and extending downward in heat exchange relation with an uninsulated outer surface of said receptacle, the intake o f said downiow portion being from a region of the refrigerated space remote from said receptacle, thermostatic means controlling the intake of said portion and means for retarding the velocity of the downfiow to maintain a body of the air in heat exchange relation'with'the wall of the container for a relatively long time. v

8. A refrigerator and a refrigerating system therein, including a substantially vgastight metal receptacle for solid carbon dioxide, very highly insulated against heat but having one wall exposed, in combination with means for transferring heat to said wall by convection from the refrigerated space, including a downflow conduit extending downward in heat-exchange relation with said exposed wall of said receptacle, the heat exchange portion of the downflow conduit being of great width'as compared with the inlet and of great flow section as compared with the outlet and being located-outside of said refrigerated space. o 9. A refrigerator having therein a refrigerating apparatus comprising an insulated solid carbon dioxide container, a conduit for circulating atmosphere having its intake in a remote portion of the refrigerated chamber and extending in heat exchange relation ,to said refrigerant container; and a carbon dioxide gas outlet conduit leading from said refrigerant container to remote portions of said refrigerated chamber, and means whereby gas from outlet conduit may be discharged into the intake of the first mentioned conduit.

' 10. A refrigerator having therein a refrigerating apparatus comprising an insulated y solid carbon dioxide container, a conduit for circulating atmosphere having its intake in a remote portion of the refrigerated chamber which includes highly insulating solid car.

bon dioxide from direct heat absorption from the refrigerated space; and conducting all of the gas' from said solid into heat exchange relation with the refrigerated space and discharging all of it outside of said space; and

applying heat to said solid carbon dioxide through a metallic conductor which is located outside of said refrigerated space by thermo circulation of air of the refrigerated space in heat exchange relation to said conductor, thereby making the rate of sublimation of gas dependent mainly on the temperature of the air of said refrigerated space.

12. A'method' of controlling distribution of refrigerating effects of solid carbon dioxide, which includes highly insulating solid carbon dioxide from direct heat absorption from the refrigerated space; and conducting all of the gasy from said solid into heat exchange relation with the refrigerated space and discharging all of it outside of said space; and applying heat to said solid carbon dioxide through a metallic conductor which is located outside of said refrigerated space by thermo circulation of air of the refrigerated space in heat exchange relation to said conductor, thereby making the rate of sublimation of gas dependent mainly on the temperature of the air of said refrigerated space, and regulating said temperature by regulating the rate of fiow of said air.

13. Amethod of controlling distribution of refrigerant effects of solid carbon dioxide, which includes highly insulating solid carbon dioxide from direct heat absorption from the refrigerated space; and conducting all of the gas from said solid into heat exchange relation with the refrigerated space and discharging all of it outside of said space; and applying heat to said solid carbon dioxide through a metallic conductor which is located outside of said refrigerated space by thermo circulation of air of the refrigerated space in heat exchange relation to said conductor, .thereby making the rate of sublimation of gas dependent mainly on the temperature ofthe air of said refrigerated space, and regulating said temperature by regulating the rate of flow of said air by and in accordance with the temperature of the air flowing toward said conductor.

14. Ainethod of controlling.distribution of refrigerant effects of solid carbon dioxide, which includes applying heat to said solid carbon dioxide through armetallic conductor by thermo circulation of atmosphere from the refrigerated space7 the down leg of said circulation being confined' and guided in heat exchange relation with said conductor; and controlling discharge of carbon dioxide gas evaporating from said solid, so as to maintain a substantially homogeneous atmosphere throughout said thermo circuit.

Signed, at New York, in the county of New York and State of NewYork, this 22nd day of December, A. D. 1980.

y DAVID H. IHLLEFFER. CHARLES L. JONES. 

